[s-cars] Re: Negative Boost-Negative Schmoost

[Steve Voit]

Hi Hap:
I started the negative boost thread cause I don't think the ideas get enough
play in our S-Heads (you and a few others excepted).  My purpose in
mentioning boost controllers is hopefully not to miss the point, but to
understand what Julien Edgar means when he says (article part 5) that he
needs a new boost contol system...  He systematically eliminated restrictors
(check), got positive pressure in the airbox (check), and then .. reports on
problems, which is where he leaves the reader:
"with the major improvement in flow through the intake, the stutters started
to affect the car badly... of course, if you increase cylinder filling you'd
expect a car on the edge of detonation to detonate; and that was what it
appeared was happening"
(with higher octane in the tank) "yes, it was better - but then I noticed
that boost was always lower!  Aaaahhh! the ECU appeared to be dropping boost
to keep the power the same, ignoring the benefits that could be had from the
new high-flow intake system and better fuel!  I was going around in circles
while the Audi ECU thumbed its nose at me"
Summary: Power did not respond to better intake flow, with initially
knowck-triggered ignition retard then falling ECU-controlled boost the
suspected culprit
(was there ever an article #6?)

My car is nearly stock (Mihnea software) and I'm attracted to improved air
intake efficiency; I just don't know what to make of Mr. Edgar's outcome.
Can you shed some light on it from the standpoint of my own expected
experience?  What, if any, mods would I need to make in order to accommodate
the change?
Steve, raising dahkine questions in Seattle, V.

(clip)
Message: 5
Date: Tue, 9 Nov 2004 13:27:55 EST
From: CaptMagu at aol.com
Subject: [s-cars] Negative Boost-Negative Schmoost
To: s-car-list at audifans.com
Message-ID: <1ac.2b14972a.2ec2662b at aol.com>
Content-Type: text/plain; charset="US-ASCII"

s-heads

I just got home late last night and have been reading these posts with some
humor. The Julian Edgar set of 5 articles should be mandatory reading for
anyone upgrading their s-car not matter what level they aspire to. He does
some
very detailed testing and never makes assumptions on his findings. Some of
which
were quite surprising to him. Someone mentioned his DIY boost controller and
I
think they missed the point. Julian was not trying to increase his boost
level but was instead trying to defeat wastegate creep, a devious villain
indeed.

Anything and everything you can do to increase flow to the turbo and
decrease
restrictions enroute to the throttle body will pay dividends to throttle
response and boost threshold. I was able to lower my boost threshold by
600rpms as
I slowly modified the different pieces of my intake and charge air track. I
also have a Big Bore throttle body, an enlarged, ported, and drilled(to
remove
the channels that are used for the lower mounting bolts) intake manifold
system and a ported and honed head. This is a shot of my intake system.

http://pictureposter.audiworld.com/15038/pic00155.jpg

Mike Pederson was the source for this steal from The boys and girls at
FoMoCo. It is a snorkel cold air box from a supercharged   SVT Mustang or
Pederhousen Big Ford Filter Kit(PBFFK)tm. Mounted to the top of it is a 92mm
ID 928 S4
Pederhousen Big MAF(PBMAF)tm. With the stock oil filter tossed in favor of a
very large Earl's unit mounted at the stock I/C location the PBFFK mounts in
there with no problem. I do have to be careful when driving during wet days
but
in 4 years, I have had no problems. So, get out there and head to Home Depot
and put some flow in those s-cars.

Hap, wit dahkine flow in Evahboost, Maguire